1950s studio question: how often did engineers clean the machine heads?

When studios relied exclusively on tape to make recordings, how often did engineers clean and demagnetize the tape paths of their machines? Was every label, studio or engineer different about their maintenance habits, or did they follow the same X-number of hours as consumer recommendations? And did they clean their heads the way we do today? Cotton swabs and wood alcohol?

Looking for an answer to obscure questions that no one else is probably interested in, but I thought I'd ask anyway.

Steve?

 

I have afriend who works at Medimmune doing calibrations. They make drugs for human use. If it outputs any sort of data, he checks it. Music is no less inportant.

 

God, don't use cotton swabs. Use Texwipes:

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_7vjnf8fpvf_b

The little 4x4" Texwipes are perfect for swabbing alcohol on the heads. If you can't pull the head cover off and can't get to the heads, then you'll need a chamois swab on a stick. I believe most electronics supply stores still carry them.

I agree with Steve about cleaning the heads on every tape reel change, but in truth, so much analogue these days is old, you may find you have to clean the tape two or three times per reel -- like on a splice or a song change or something.

Head alignment was also critical, and for that you need a factory alignment tape or one made by MRL or similar companies. Those ain't cheap.

 

After every recording? Crazy!

So how important is demag, really?

 

Those wipes look like a better idea. Thanks, vidiot.

 

How often are tubes changed...just when they die I presume. John M.

 

Cool!

 

Marc, any audible signs that would prompt me to know that I should clean my heads mid-reel? I had a red oxide tape that shedded so bad I had to clean the tape path after every play. I ash canned it.

 

Muffled sound, wavering, muddiness. I once had a 1954 35mm mag track where I could only play it for about 5 minutes before the heads would clog. I wound up transferring it in 3-minute sections, cleaning it and noting that there was only a teeny bit of oxide coming off the head as long as I didn't let it go too much further. Other than that, it sounded spectacular. A safety copy made by the studio in 1980 sounded ten times worse, because they did a bad job of transferring it plus the mag was suffering from stiction.

 

Crazy?. That's a LOT of tape going over the tape path. I do the same when recording and I only have a late '70s TEAC RTR. I do exactly the same with cassette recordings.

 

In the open reel world, not crazy. Sensible standard operating practice.

 

In the late 80's I worked at a radio station that had been on the air since the 1930's. They had tons of vintage equipment. They had an 8-track reel to reel machine and it was cleaned before each use. By this time it wasn't getting much use, but you cleaned it before each use. Some of the other stuff, maybe once a week.

 

I have two tape machines even though I play mostly vinyl and the occasional CD. I clean the heads and rollers before each reel I play. I use Q-tips and alcohol for the heads and Amp Audio Pro Pinch Roller Cleaner for the rubber parts.

 

Demagnetizing the heads is really more of a safety thing than anything else. You may never have a problem is you don't do it, but if there is a problem one time it can be a big deal.

 

So, assuming 15 ips and 10 inch reels, the tape must have been changed for every 45 minutes of material. If a song took many takes that exchausted one reel, then it's likely they'd clean the tape path between takes when changing the reel out?

 

What sort of problems can happen?

 

Partial erasure of high frequencies.

 

So even if there isn't a lot of oxide buildup, there will be a sonic improvement if the heads are cleaned more often than not?

 

Not only that, but if you're really finicky you will realign for each reel. As silly as this sounds, each reel will likely have a slightly different response. In fact, if you set the machine up at the head of the reel, it will likely be off at the tail. We're not talking a great deal but it can be as much as a db.

It's another reason I have little faith in using included tones to do an absolute alignment. If one had a guarantee that the tones at the head of a reel are from the same exact reel as the song, then they're probably pretty safe to use. More often, the tones are spliced onto the master reel from another reel. That's why I think tones are great for getting close to an alignment, but the ears should always take precedent for fine tuning.

 

I was responding to the comment about cleaning before each tape. That practice makes sense to me and I am sure they did this in the 1950's as well. Sorry if I was off topic.

 

There CAN be. That doesn't mean there always will be. Once again, it's mainly a safeguard.

The amount of oxidation on the tape path can vary depending on the condition and types of tapes played on the machine and even things like the mechanical setup.

Even if there is a bit of residue that wouldn't seem to affect performance, it's best to remove it because it seems that once the tape path gets dirty, it seems to attract more dirt. The process is also cumulative, and can build up over time. I've actually been in situations where the tape path had to be cleaned several times during the playing of a reel.

 

So what would the engineer announce to the musicians if they had to change a reel between takes and decided to realign at the same time? STANDBY? And how fast could they clean/align/demag under pressure?

If the artist went into the booth to listen to playbacks after the session finished, I assume they would still clean between reels?